1. Field of Invention
This invention relates to automatic valves, specifically to the independent opening and closing of flow ports from system pressure applied to one port, with back flow protection created against pressure applied to any other ports, allowing the independent operation of multiple sprinkler zones with one fertilizer storage tank.
2. Description of Prior Art
The initial use of this product would be to enable a multiple zone irrigation system to use one fertilizer storage tank, to inject fertilizer independently to all sprinkler zones, when connected to the downstream or non-pressure side of the sprinkler zone valve. This is accomplished by opening a flow outlet and inlet port to the fertilizer storage tank, when the sprinkler zone valve is opened and the sprinkler zone is pressurized, without allowing flow into the sprinkler zones that are not open, as well as not allowing back pressure from the tank or opened zones to affect the predetermined opening pressure required to open the valve.
Various methods of central sprinkler fertilizing units have been developed, but due to backflow prevention requirements, one unit had to be attached to each zone when a zone valve with an atmospheric vacuum breaker was used. Some of the disadvantages related to that are the additional cost of additional units and the added time required to monitor and fill each individual unit. Also, the prior installation was complicated by the fact that the unit must be six inches below the vacuum breaker to meet code requirements. This meant piping would have to be changed to accommodate the addition of the tank assembly.
The only other means of using only one fertilizer storage tank for a multiple zone sprinkler system, that complies with back flow prevention codes would require connecting to the sprinkler main line before the zone valves and installing a reduced pressure backflow preventer or pressure vacuum breaker, depending on the plumbing code requirements of the specific area. This can be very expensive and labor intensive.
The U.S. Pat. No. 3,572,850, pressure responsive splitter valve by Harold B. Schultz uses multiple flow ports within a closed loop system to maintain a pressure balanced system. It does not create an engineered unbalanced system which is required to accomplish the flow requirements of my invention.
The U.S. Pat. No. 5,271,428, adjustable differential pressure valve by Charles S. Dunn uses an adjustable pressure differential to open flow to multiple ports. It does not open a return port which is required in the application performed by my invention.
The U.S. Pat. No. 5,040,559, modulating positive shutoff mechanism by James H. Ewing is designed to control flow through singular import and output ports. It does not open multiple ports to divert flow and allow for reinjection into the flow line, which is required to accomplish the flow requirements of my invention.
The U.S. Pat. No. 3,858,607, three-way, two-position diverter valve by William J. Baker uses an actuator to divert flow through multiple ports. It requires an actuator with outside power source and does not allow for inlet and outlet ports, but deals with outlet ports only, where my invention does not require outside power to open the ports and allows both inlet and outlet flow.
The U.S. Pat. No. 4,177,840, pressure regulation and flow control valve with combination needle and check valves by James A. Neff regulates flow and pressure in one flow through port. It does not divert flow to other inlet and outlet ports to create opening and closing independent zones which is necessary to meet the flow requirements of my invention. The U.S. Pat. No. 5,133,386 balanced, pressure-flow-compensated, single-stage servovalve by Garth L. Magee maintains a balanced flow through the use of multiple ports within a closed system. It accommodates inlet and outlet flow for pressure balance only. It does not allow independent flow to an outside source and reinjection to the original flow which is required to meet the flow requirements of my invention.
The U.S. Pat. No. 1,287,258 automatic valve by Edward William Discher is designed to open two inlet ports at a predetermined pressure allowing flow unless the inlet pressure falls below the predetermined level. It does not stop back flow in that it would open when there is adequate back pressure to overcome the spring pressure because the valve seal 12 is exposed to back pressure through port 14. Back pressure against valve seal 20 would also increase the amount of pressure required in the inlet port to open the valve. My invention will not open from back pressure and back pressure will not affect the amount of pressure required to open my valve. This is required to meet the flow requirements of my invention in that back flow from opened zones cannot be allowed to enter unopened zones and back pressure from cannot interfere with the opening of the valve when it is pressurized as the zone opens.
The U.S. Pat. No. 1,257,070 automatic valve by Edward William Discher is designed to open two inlet ports at a predetermined pressure allowing flow unless the inlet pressure falls below the predetermined level. It does not stop back flow and would open when back pressure is adequate to overcome the spring pressure because the valve seal 26 is exposed to back pressure from port 9. Back pressure would motivate the valve to move against spring 23, into the open position. Back pressure would increase the amount of pressure required in the inlet port to open the valve because valve seal 22 does not seal cavity 12 from back pressure from port 11 when the valve is in the closed position. In a back pressure condition, pressure would enter cavity 12 from port 11, adding to the pressure applied by spring 23 to maintain the valve in the closed position. My invention will not open from back pressure and back pressure will not affect the amount of pressure required to open my valve. This is required to meet the flow requirements of my invention, in that back flow cannot be allowed to enter unopened zones and back pressure cannot interfere with the opening of the valve when it is pressurized as the zone opens.
My invention solves the problem of multiple sprinkler zones with atmospheric vacuum breakers requiring individual fertilizer dispensing units to meet back flow prevention codes. It enables multiple sprinkler zones to work independently with one storage tank source without the requirement of outside power source. It opens only when a predetermined amount of pressure enters one inlet port as the sprinkler zone opens and is pressurized. It will not open in response to pressure entering any other inlet or outlet ports of the valve. Pressure entering the other inlet and outlet ports will not affect the amount of pressure required to open the valve. This check valve action prevents fertilizer from flowing into unopened sprinkler zones. To my knowledge, this problem hasn't been addressed specifically in the past.